//------------------------------------------------------------------------------
// <copyright file="SchemaMapping.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
//------------------------------------------------------------------------------

namespace System.Data.ProviderBase {

    using System.Collections.Generic;
    using System.Data;
    using System.Data.Common;
    using System.Diagnostics;
    using System.Globalization;

    sealed internal class SchemaMapping {

        // DataColumns match in length and name order as the DataReader, no chapters
        private const int MapExactMatch = 0;

        // DataColumns has different length, but correct name order as the DataReader, no chapters
        private const int MapDifferentSize = 1;

        // DataColumns may have different length, but a differant name ordering as the DataReader, no chapters
        private const int MapReorderedValues = 2;

        // DataColumns may have different length, but correct name order as the DataReader, with chapters
        private const int MapChapters = 3;

        // DataColumns may have different length, but a differant name ordering as the DataReader, with chapters
        private const int MapChaptersReordered = 4;

        // map xml string data to DataColumn with DataType=typeof(SqlXml)
        private const int SqlXml = 1;

        // map xml string data to DataColumn with DataType=typeof(XmlDocument)
        private const int XmlDocument = 2;

        private readonly DataSet _dataSet; // the current dataset, may be null if we are only filling a DataTable
        private DataTable _dataTable; // the current DataTable, should never be null

        private readonly DataAdapter _adapter;
        private readonly DataReaderContainer _dataReader;
        private readonly DataTable _schemaTable;  // will be null if Fill without schema
        private readonly DataTableMapping _tableMapping;

        // unique (generated) names based from DataReader.GetName(i)
        private readonly string[] _fieldNames;

        private readonly object[] _readerDataValues;
        private object[] _mappedDataValues; // array passed to dataRow.AddUpdate(), if needed

        private int[] _indexMap;     // index map that maps dataValues -> _mappedDataValues, if needed
        private bool[] _chapterMap;  // which DataReader indexes have chapters

        private int[] _xmlMap; // map which value in _readerDataValues to convert to a Xml datatype, (SqlXml/XmlDocument)

        private int _mappedMode; // modes as described as above
        private int _mappedLength;

        private readonly LoadOption _loadOption;

        internal SchemaMapping(DataAdapter adapter, DataSet dataset, DataTable datatable, DataReaderContainer dataReader, bool keyInfo,
                                    SchemaType schemaType, string sourceTableName, bool gettingData,
                                    DataColumn parentChapterColumn, object parentChapterValue) {
            Debug.Assert(null != adapter, "adapter");
            Debug.Assert(null != dataReader, "dataReader");
            Debug.Assert(0 < dataReader.FieldCount, "FieldCount");
            Debug.Assert(null != dataset || null != datatable, "SchemaMapping - null dataSet");
            Debug.Assert(SchemaType.Mapped == schemaType || SchemaType.Source == schemaType, "SetupSchema - invalid schemaType");

            _dataSet = dataset;     // setting DataSet implies chapters are supported
            _dataTable = datatable; // setting only DataTable, not DataSet implies chapters are not supported
            _adapter = adapter;
            _dataReader = dataReader;

            if (keyInfo) {
                _schemaTable = dataReader.GetSchemaTable();
            }

            if (adapter.ShouldSerializeFillLoadOption()) {
                _loadOption = adapter.FillLoadOption;
            }
            else if (adapter.AcceptChangesDuringFill) {
                _loadOption = (LoadOption)4; // true
            }
            else {
                _loadOption = (LoadOption)5; //false
            }

            MissingMappingAction mappingAction;
            MissingSchemaAction schemaAction;
            if (SchemaType.Mapped == schemaType) {
                mappingAction = _adapter.MissingMappingAction;
                schemaAction = _adapter.MissingSchemaAction;
                if (!ADP.IsEmpty(sourceTableName)) { // MDAC 66034
                    _tableMapping = _adapter.GetTableMappingBySchemaAction(sourceTableName, sourceTableName, mappingAction);
                }
                else if (null != _dataTable) {
                    int index = _adapter.IndexOfDataSetTable(_dataTable.TableName);
                    if (-1 != index) {
                        _tableMapping = _adapter.TableMappings[index];
                    }
                    else {
                        switch (mappingAction) {
                        case MissingMappingAction.Passthrough:
                            _tableMapping = new DataTableMapping(_dataTable.TableName, _dataTable.TableName);
                            break;
                        case MissingMappingAction.Ignore:
                            _tableMapping = null;
                            break;
                        case MissingMappingAction.Error:
                            throw ADP.MissingTableMappingDestination(_dataTable.TableName);
                        default:
                            throw ADP.InvalidMissingMappingAction(mappingAction);
                        }
                    }
                }
            }
            else if (SchemaType.Source == schemaType) {
                mappingAction = System.Data.MissingMappingAction.Passthrough;
                schemaAction = Data.MissingSchemaAction.Add;
                if (!ADP.IsEmpty(sourceTableName)) { // MDAC 66034
                    _tableMapping = DataTableMappingCollection.GetTableMappingBySchemaAction(null, sourceTableName, sourceTableName, mappingAction);
                }
                else if (null != _dataTable) {
                    int index = _adapter.IndexOfDataSetTable(_dataTable.TableName); // MDAC 66034
                    if (-1 != index) {
                        _tableMapping = _adapter.TableMappings[index];
                    }
                    else {
                        _tableMapping = new DataTableMapping(_dataTable.TableName, _dataTable.TableName);
                    }
                }
            }
            else {
                throw ADP.InvalidSchemaType(schemaType);
            }

            if (null != _tableMapping) {
                if (null == _dataTable) {
                    _dataTable = _tableMapping.GetDataTableBySchemaAction(_dataSet, schemaAction);
                }
                if (null != _dataTable) {
                    _fieldNames = GenerateFieldNames(dataReader);

                    if (null == _schemaTable) {
                        _readerDataValues = SetupSchemaWithoutKeyInfo(mappingAction, schemaAction, gettingData, parentChapterColumn, parentChapterValue);
                    }
                    else {
                        _readerDataValues = SetupSchemaWithKeyInfo(mappingAction, schemaAction, gettingData, parentChapterColumn, parentChapterValue);
                    }
                }
                // else (null == _dataTable) which means ignore (mapped to nothing)
            }
        }

        internal DataReaderContainer DataReader {
            get {
                return _dataReader;
            }
        }

        internal DataTable DataTable {
            get {
                return _dataTable;
            }
        }

        internal object[] DataValues {
            get {
                return _readerDataValues;
            }
        }

        internal void ApplyToDataRow(DataRow dataRow) {
            DataColumnCollection columns = dataRow.Table.Columns;
            _dataReader.GetValues(_readerDataValues);

            object[] mapped = GetMappedValues();
            bool[] readOnly = new bool[mapped.Length];
            for (int i = 0; i < readOnly.Length; ++i) {
                readOnly[i] = columns[i].ReadOnly;
            }

            try {
                try {
                    // allow all columns to be written to
                    for (int i = 0; i < readOnly.Length; ++i) {
                        if (0 == columns[i].Expression.Length) { // WebData 110773
                            columns[i].ReadOnly = false;
                        }
                    }

                    for(int i = 0; i < mapped.Length; ++i) {
                        if (null != mapped[i]) { // MDAC 72659
                            dataRow[i] = mapped[i];
                        }
                    }
                }
                finally { // ReadOnly
                    // reset readonly flag on all columns
                    for (int i = 0; i < readOnly.Length; ++i) {
                        if (0 == columns[i].Expression.Length) { // WebData 110773
                            columns[i].ReadOnly = readOnly[i];
                        }
                    }
                }
            }
            finally { // FreeDataRowChapters
                if (null != _chapterMap) {
                    FreeDataRowChapters();
                }
            }
        }

        private void MappedChapterIndex() { // mode 4
            int length = _mappedLength;

            for (int i = 0; i < length; i++) {
                int k = _indexMap[i];
                if (0 <= k) {
                    _mappedDataValues[k] = _readerDataValues[i]; // from reader to dataset
                    if (_chapterMap[i]) {
                        _mappedDataValues[k] = null; // InvalidCast from DataReader to AutoIncrement DataColumn
                    }
                }
            }
        }

        private void MappedChapter() { // mode 3
            int length = _mappedLength;

            for (int i = 0; i < length; i++) {
                _mappedDataValues[i] = _readerDataValues[i]; // from reader to dataset
                if (_chapterMap[i]) {
                    _mappedDataValues[i] = null; // InvalidCast from DataReader to AutoIncrement DataColumn
                }
            }
        }

        private void MappedIndex() { // mode 2
            Debug.Assert(_mappedLength == _indexMap.Length, "incorrect precomputed length");

            int length = _mappedLength;
            for (int i = 0; i < length; i++) {
                int k = _indexMap[i];
                if (0 <= k) {
                    _mappedDataValues[k] = _readerDataValues[i]; // from reader to dataset
                }
            }
        }

        private void MappedValues() { // mode 1
            Debug.Assert(_mappedLength == Math.Min(_readerDataValues.Length, _mappedDataValues.Length), "incorrect precomputed length");

            int length = _mappedLength;
            for (int i = 0; i < length; ++i) {
                _mappedDataValues[i] = _readerDataValues[i]; // from reader to dataset
            };
        }

        private object[] GetMappedValues() { // mode 0
            if (null != _xmlMap) {
                for(int i = 0; i < _xmlMap.Length; ++i) {
                    if (0 != _xmlMap[i]) {
                        // get the string/SqlString xml value
                        string xml = _readerDataValues[i] as string;
                        if ((null == xml) && (_readerDataValues[i] is System.Data.SqlTypes.SqlString)) {
                            System.Data.SqlTypes.SqlString x = (System.Data.SqlTypes.SqlString)_readerDataValues[i];
                            if (!x.IsNull) {
                                xml = x.Value;
                            }
                            else {
                                switch(_xmlMap[i]) {
                                case SqlXml:
                                    // map strongly typed SqlString.Null to SqlXml.Null
                                    _readerDataValues[i] = System.Data.SqlTypes.SqlXml.Null;
                                    break;
                                default:
                                    _readerDataValues[i] = DBNull.Value;
                                    break;
                                }
                            }
                        }
                        if (null != xml) {
                            switch(_xmlMap[i]) {
                            case SqlXml: // turn string into a SqlXml value for DataColumn
                                System.Xml.XmlReaderSettings settings = new System.Xml.XmlReaderSettings();
                                settings.ConformanceLevel = System.Xml.ConformanceLevel.Fragment;
                                System.Xml.XmlReader reader = System.Xml.XmlReader.Create(new System.IO.StringReader(xml), settings, (string)null);
                                _readerDataValues[i] = new System.Data.SqlTypes.SqlXml(reader);
                                break;
                            case XmlDocument: // turn string into XmlDocument value for DataColumn
                                System.Xml.XmlDocument document = new System.Xml.XmlDocument();
                                document.LoadXml(xml);
                                _readerDataValues[i] = document;
                                break;
                            }
                            // default: let value fallthrough to DataSet which may fail with ArgumentException
                        }
                    }
                }
            }

            switch(_mappedMode) {
            default:
            case MapExactMatch:
                Debug.Assert(0 == _mappedMode, "incorrect mappedMode");
                Debug.Assert((null == _chapterMap) && (null == _indexMap) && (null == _mappedDataValues), "incorrect MappedValues");
                return _readerDataValues;  // from reader to dataset
            case MapDifferentSize:
                Debug.Assert((null == _chapterMap) && (null == _indexMap) && (null != _mappedDataValues), "incorrect MappedValues");
                MappedValues();
                break;
            case MapReorderedValues:
                Debug.Assert((null == _chapterMap) && (null != _indexMap) && (null != _mappedDataValues), "incorrect MappedValues");
                MappedIndex();
                break;
            case MapChapters:
                Debug.Assert((null != _chapterMap) && (null == _indexMap) && (null != _mappedDataValues), "incorrect MappedValues");
                MappedChapter();
                break;
            case MapChaptersReordered:
                Debug.Assert((null != _chapterMap) && (null != _indexMap) && (null != _mappedDataValues), "incorrect MappedValues");
                MappedChapterIndex();
                break;
            }
            return _mappedDataValues;
        }

        internal void LoadDataRowWithClear() {
            // for FillErrorEvent to ensure no values leftover from previous row
            for (int i = 0; i < _readerDataValues.Length; ++i) {
                _readerDataValues[i] = null;
            }
            LoadDataRow();
        }

        internal void LoadDataRow() {
            try {
                _dataReader.GetValues(_readerDataValues);
                object[] mapped = GetMappedValues();

                DataRow dataRow;
                switch(_loadOption) {
                case LoadOption.OverwriteChanges:
                case LoadOption.PreserveChanges:
                case LoadOption.Upsert:
                    dataRow = _dataTable.LoadDataRow(mapped, _loadOption);
                    break;
                case (LoadOption)4: // true
                    dataRow = _dataTable.LoadDataRow(mapped, true);
                    break;
                case (LoadOption)5: // false
                    dataRow = _dataTable.LoadDataRow(mapped, false);
                    break;
                default:
                    Debug.Assert(false, "unexpected LoadOption");
                    throw ADP.InvalidLoadOption(_loadOption);
                }
                if ((null != _chapterMap) && (null != _dataSet)) {
                    LoadDataRowChapters(dataRow); // MDAC 70772
                }
            }
            finally {
                if (null != _chapterMap) {
                    FreeDataRowChapters(); // MDAC 71900
                }
            }
        }

        private void FreeDataRowChapters() {
            for(int i = 0; i < _chapterMap.Length; ++i) {
                if (_chapterMap[i]) {
                    IDisposable disposable = (_readerDataValues[i] as IDisposable);
                    if (null != disposable) {
                        _readerDataValues[i] = null;
                        disposable.Dispose();
                    }
                }
            }
        }

        internal int LoadDataRowChapters(DataRow dataRow) {
            int datarowadded = 0;

            int rowLength = _chapterMap.Length;
            for(int i = 0; i < rowLength; ++i) {
                if (_chapterMap[i]) {
                    object readerValue = _readerDataValues[i];
                    if ((null != readerValue) && !Convert.IsDBNull(readerValue)) { // MDAC 70441
                        _readerDataValues[i] = null;

                        using (IDataReader nestedReader = (IDataReader) readerValue) {
                            if (!nestedReader.IsClosed) {
                                Debug.Assert(null != _dataSet, "if chapters, then Fill(DataSet,...) not Fill(DataTable,...)");

                                object parentChapterValue;
                                DataColumn parentChapterColumn;
                                if (null == _indexMap) {
                                    parentChapterColumn = _dataTable.Columns[i];
                                    parentChapterValue = dataRow[parentChapterColumn];
                                }
                                else {
                                    parentChapterColumn = _dataTable.Columns[_indexMap[i]];
                                    parentChapterValue = dataRow[parentChapterColumn];
                                }

                                // correct on Fill, not FillFromReader
                                string chapterTableName = _tableMapping.SourceTable + _fieldNames[i]; // MDAC 70908

                                DataReaderContainer readerHandler = DataReaderContainer.Create(nestedReader, _dataReader.ReturnProviderSpecificTypes);
                                datarowadded += _adapter.FillFromReader(_dataSet, null, chapterTableName, readerHandler, 0, 0, parentChapterColumn, parentChapterValue);
                            }
                        }
                    }
                }
            }
            return datarowadded;
        }

        private int[] CreateIndexMap(int count, int index) {
            int[] values = new int[count];
            for (int i = 0; i < index; ++i) {
                values[i] = i;
            }
            return values;
        }

        private static string[] GenerateFieldNames(DataReaderContainer dataReader) {
            string[] fieldNames = new string[dataReader.FieldCount];
            for(int i = 0; i < fieldNames.Length; ++i) {
                fieldNames[i] = dataReader.GetName(i);
            }
            ADP.BuildSchemaTableInfoTableNames(fieldNames);
            return fieldNames;
        }

        private DataColumn[] ResizeColumnArray(DataColumn[] rgcol, int len) {
            Debug.Assert(rgcol != null, "invalid call to ResizeArray");
            Debug.Assert(len <= rgcol.Length, "invalid len passed to ResizeArray");
            DataColumn[] tmp = new DataColumn[len];
            Array.Copy(rgcol, tmp, len);
            return tmp;
        }

        private void AddItemToAllowRollback(ref List<object> items, object value) {
            if (null == items) {
                items = new List<object>();
            }
            items.Add(value);
        }

        private void RollbackAddedItems(List<object> items) {
            if (null != items) {
                for (int i = items.Count-1; 0 <= i; --i) {
                    // remove columns that were added now that we are failing
                    if (null != items[i]) {
                        DataColumn column = (items[i] as DataColumn);
                        if (null != column) {
                            if (null != column.Table) {
                                column.Table.Columns.Remove(column);
                            }
                        }
                        else {
                            DataTable table = (items[i] as DataTable);
                            if (null != table) {
                                if (null != table.DataSet) {
                                    table.DataSet.Tables.Remove(table);
                                }
                            }
                        }
                    }
                }
            }
        }

        private object[] SetupSchemaWithoutKeyInfo(MissingMappingAction mappingAction, MissingSchemaAction schemaAction, bool gettingData, DataColumn parentChapterColumn, object chapterValue) {
            int[] columnIndexMap = null;
            bool[] chapterIndexMap = null;

            int mappingCount = 0;
            int count = _dataReader.FieldCount;

            object[] dataValues = null;
            List<object> addedItems = null;
            try {
                DataColumnCollection columnCollection = _dataTable.Columns;
                columnCollection.EnsureAdditionalCapacity(count + (chapterValue != null ? 1 : 0));
                // We can always just create column if there are no existing column or column mappings, and the mapping action is passthrough
                bool alwaysCreateColumns = ((_dataTable.Columns.Count == 0) && ((_tableMapping.ColumnMappings == null) || (_tableMapping.ColumnMappings.Count == 0)) && (mappingAction == MissingMappingAction.Passthrough));

                for (int i = 0; i < count; ++i) {

                    bool ischapter = false;
                    Type fieldType = _dataReader.GetFieldType(i);

                    if (null == fieldType) {
                        throw ADP.MissingDataReaderFieldType(i);
                    }

                    // if IDataReader, hierarchy exists and we will use an Int32,AutoIncrementColumn in this table
                    if (typeof(IDataReader).IsAssignableFrom(fieldType)) {
                        if (null == chapterIndexMap) {
                            chapterIndexMap = new bool[count];
                        }
                        chapterIndexMap[i] = ischapter = true;
                        fieldType = typeof(Int32);
                    }
                    else if (typeof(System.Data.SqlTypes.SqlXml).IsAssignableFrom(fieldType)) {
                        if (null == _xmlMap) { // map to DataColumn with DataType=typeof(SqlXml)
                            _xmlMap = new int[count];
                        }
                        _xmlMap[i] = SqlXml; // track its xml data
                    }
                    else if (typeof(System.Xml.XmlReader).IsAssignableFrom(fieldType)) {
                        fieldType = typeof(String); // map to DataColumn with DataType=typeof(string)
                        if (null == _xmlMap) {
                            _xmlMap = new int[count];
                        }
                        _xmlMap[i] = XmlDocument; // track its xml data
                    }

                    DataColumn dataColumn;
                    if (alwaysCreateColumns) {
                        dataColumn = DataColumnMapping.CreateDataColumnBySchemaAction(_fieldNames[i], _fieldNames[i], _dataTable, fieldType, schemaAction);
                    }
                    else {
                        dataColumn = _tableMapping.GetDataColumn(_fieldNames[i], fieldType, _dataTable, mappingAction, schemaAction);
                    }

                    if (null == dataColumn) {
                        if (null == columnIndexMap) {
                            columnIndexMap = CreateIndexMap(count, i);
                        }
                        columnIndexMap[i] = -1;
                        continue; // null means ignore (mapped to nothing)
                    }
                    else if ((null != _xmlMap) && (0 != _xmlMap[i])) {
                        if (typeof(System.Data.SqlTypes.SqlXml) == dataColumn.DataType) {
                            _xmlMap[i] = SqlXml;
                        }
                        else if (typeof(System.Xml.XmlDocument) == dataColumn.DataType) {
                            _xmlMap[i] = XmlDocument;
                        }
                        else {
                            _xmlMap[i] = 0; // datacolumn is not a specific Xml dataType, i.e. string

                            int total = 0;
                            for(int x = 0; x < _xmlMap.Length; ++x) {
                                total += _xmlMap[x];
                            }
                            if (0 == total) { // not mapping to a specific Xml datatype, get rid of the map
                                _xmlMap = null;
                            }
                        }
                    }

                    if (null == dataColumn.Table) {
                        if (ischapter) {
                            dataColumn.AllowDBNull = false;
                            dataColumn.AutoIncrement = true;
                            dataColumn.ReadOnly = true;
                        }
                        AddItemToAllowRollback(ref addedItems, dataColumn);
                        columnCollection.Add(dataColumn);
                    }
                    else if (ischapter && !dataColumn.AutoIncrement) {
                        throw ADP.FillChapterAutoIncrement();
                    }


                    if (null != columnIndexMap) {
                        columnIndexMap[i] = dataColumn.Ordinal;
                    }
                    else if (i != dataColumn.Ordinal) {
                        columnIndexMap = CreateIndexMap(count, i);
                        columnIndexMap[i] = dataColumn.Ordinal;
                    }
                    // else i == dataColumn.Ordinal and columnIndexMap can be optimized out

                    mappingCount++;
                }
                bool addDataRelation = false;
                DataColumn chapterColumn = null;
                if (null != chapterValue) { // add the extra column in the child table
                    Type fieldType = chapterValue.GetType();

                    chapterColumn = _tableMapping.GetDataColumn(_tableMapping.SourceTable, fieldType, _dataTable, mappingAction, schemaAction);
                    if (null != chapterColumn) {

                        if (null == chapterColumn.Table) {
                            AddItemToAllowRollback(ref addedItems, chapterColumn);
                            columnCollection.Add(chapterColumn);
                            addDataRelation = (null != parentChapterColumn);
                        }
                        mappingCount++;
                    }
                }

                if (0 < mappingCount) {
                    if ((null != _dataSet) && (null == _dataTable.DataSet)) {
                        // Allowed to throw exception if DataTable is from wrong DataSet
                        AddItemToAllowRollback(ref addedItems, _dataTable);
                        _dataSet.Tables.Add(_dataTable);
                    }
                    if (gettingData) {
                        if (null == columnCollection) {
                            columnCollection = _dataTable.Columns;
                        }
                        _indexMap = columnIndexMap;
                        _chapterMap = chapterIndexMap;
                        dataValues = SetupMapping(count, columnCollection, chapterColumn, chapterValue);
                    }
                    else {
                        // debug only, but for retail debug ability
                        _mappedMode = -1;
                    }
                }
                else {
                    _dataTable = null;
                }

                if (addDataRelation) {
                    AddRelation(parentChapterColumn, chapterColumn);
                }

            }
            catch (Exception e) {
                // 
                if (ADP.IsCatchableOrSecurityExceptionType(e)) {
                    RollbackAddedItems(addedItems);
                }
                throw;
            }
            return dataValues;
        }

        private object[] SetupSchemaWithKeyInfo(MissingMappingAction mappingAction, MissingSchemaAction schemaAction, bool gettingData, DataColumn parentChapterColumn, object chapterValue) {
            // must sort rows from schema table by ordinal because Jet is sorted by coumn name
            DbSchemaRow[] schemaRows = DbSchemaRow.GetSortedSchemaRows(_schemaTable, _dataReader.ReturnProviderSpecificTypes); // MDAC 60609
            Debug.Assert(null != schemaRows, "SchemaSetup - null DbSchemaRow[]");
            Debug.Assert(_dataReader.FieldCount <= schemaRows.Length, "unexpected fewer rows in Schema than FieldCount");

            if (0 == schemaRows.Length) {
                _dataTable = null;
                return (object[])null;
            }

            // Everett behavior, always add a primary key if a primary key didn't exist before
            // Whidbey behavior, same as Everett unless using LoadOption then add primary key only if no columns previously existed
            bool addPrimaryKeys = (((0 == _dataTable.PrimaryKey.Length) && ((4 <= (int)_loadOption) || (0 == _dataTable.Rows.Count)))
                                    || (0 == _dataTable.Columns.Count)); // MDAC 67033

            DataColumn[] keys = null;
            int keyCount = 0;
            bool isPrimary = true; // assume key info (if any) is about a primary key

            string keyBaseTable = null;
            string commonBaseTable = null;

            bool keyFromMultiTable = false;
            bool commonFromMultiTable = false;

            int[] columnIndexMap = null;
            bool[] chapterIndexMap = null;

            int mappingCount = 0;

            object[] dataValues = null;
            List<object> addedItems = null;
            DataColumnCollection columnCollection = _dataTable.Columns;
            try {
                for(int sortedIndex = 0; sortedIndex < schemaRows.Length; ++sortedIndex) {
                    DbSchemaRow schemaRow = schemaRows[sortedIndex];

                    int unsortedIndex = schemaRow.UnsortedIndex; // MDAC 67050

                    bool ischapter = false;
                    Type fieldType = schemaRow.DataType;
                    if (null == fieldType) {
                        fieldType = _dataReader.GetFieldType(sortedIndex);
                    }
                    if (null == fieldType) {
                        throw ADP.MissingDataReaderFieldType(sortedIndex);
                    }

                    // if IDataReader, hierarchy exists and we will use an Int32,AutoIncrementColumn in this table
                    if (typeof(IDataReader).IsAssignableFrom(fieldType)) {
                        if (null == chapterIndexMap) {
                            chapterIndexMap = new bool[schemaRows.Length];
                        }
                        chapterIndexMap[unsortedIndex] = ischapter = true;
                        fieldType = typeof(Int32);
                    }
                    else if (typeof(System.Data.SqlTypes.SqlXml).IsAssignableFrom(fieldType)) {
                        if (null == _xmlMap) {
                            _xmlMap = new int[schemaRows.Length];
                        }
                        _xmlMap[sortedIndex] = SqlXml;
                    }
                    else if (typeof(System.Xml.XmlReader).IsAssignableFrom(fieldType)) {
                        fieldType = typeof(String);
                        if (null == _xmlMap) {
                            _xmlMap = new int[schemaRows.Length];
                        }
                        _xmlMap[sortedIndex] = XmlDocument;
                    }

                    DataColumn dataColumn = null;
                    if (!schemaRow.IsHidden ) {
                        dataColumn = _tableMapping.GetDataColumn(_fieldNames[sortedIndex], fieldType, _dataTable, mappingAction, schemaAction);
                    }

                    string basetable = /*schemaRow.BaseServerName+schemaRow.BaseCatalogName+schemaRow.BaseSchemaName+*/ schemaRow.BaseTableName;
                    if (null == dataColumn) {
                        if (null == columnIndexMap) {
                            columnIndexMap = CreateIndexMap(schemaRows.Length, unsortedIndex);
                        }
                        columnIndexMap[unsortedIndex] = -1;

                        // if the column is not mapped and it is a key, then don't add any key information
                        if (schemaRow.IsKey) { // MDAC 90822
#if DEBUG
                            if (AdapterSwitches.DataSchema.TraceVerbose) {
                                Debug.WriteLine("SetupSchema: partial primary key detected");
                            }
#endif
                            // if the hidden key comes from a different table - don't throw away the primary key
                            // example SELECT [T2].[ID], [T2].[ProdID], [T2].[VendorName] FROM [Vendor] AS [T2], [Prod] AS [T1] WHERE (([T1].[ProdID] = [T2].[ProdID]))
                            if (keyFromMultiTable || (schemaRow.BaseTableName == keyBaseTable)) { // WebData 100376
                                addPrimaryKeys = false; // don't add any future keys now
                                keys = null; // get rid of any keys we've seen
                            }
                        }
                        continue; // null means ignore (mapped to nothing)
                    }
                    else if ((null != _xmlMap) && (0 != _xmlMap[sortedIndex])) {
                        if (typeof(System.Data.SqlTypes.SqlXml) == dataColumn.DataType) {
                            _xmlMap[sortedIndex] = SqlXml;
                        }
                        else if (typeof(System.Xml.XmlDocument) == dataColumn.DataType) {
                            _xmlMap[sortedIndex] = XmlDocument;
                        }
                        else {
                            _xmlMap[sortedIndex] = 0; // datacolumn is not a specific Xml dataType, i.e. string

                            int total = 0;
                            for(int x = 0; x < _xmlMap.Length; ++x) {
                                total += _xmlMap[x];
                            }
                            if (0 == total) { // not mapping to a specific Xml datatype, get rid of the map
                                _xmlMap = null;
                            }
                        }
                    }

                    if (schemaRow.IsKey) {
                        if (basetable != keyBaseTable) {
                            if (null == keyBaseTable) {
                                keyBaseTable = basetable;
                            }
                            else keyFromMultiTable = true;
                        }
                    }

                    if (ischapter) {
                        if (null == dataColumn.Table) {
                            dataColumn.AllowDBNull = false;
                            dataColumn.AutoIncrement = true;
                            dataColumn.ReadOnly = true;
                        }
                        else if (!dataColumn.AutoIncrement) {
                            throw ADP.FillChapterAutoIncrement();
                        }
                    }
                    else {// MDAC 67033
                        if (!commonFromMultiTable) {
                            if ((basetable != commonBaseTable) && (!ADP.IsEmpty(basetable))) {
                                if (null == commonBaseTable) {
                                    commonBaseTable = basetable;
                                }
                                else {
                                    commonFromMultiTable = true;
                                }
                            }
                        }
                        if (4 <= (int)_loadOption) {
                            if (schemaRow.IsAutoIncrement && DataColumn.IsAutoIncrementType(fieldType)) {
                                // 

                                dataColumn.AutoIncrement = true;

                                if (!schemaRow.AllowDBNull) { // MDAC 71060
                                    dataColumn.AllowDBNull = false;
                                }
                            }

                            // setup maxLength, only for string columns since this is all the DataSet supports
                            if (fieldType == typeof(string)) {
                                //@devnote:  schemaRow.Size is count of characters for string columns, count of bytes otherwise
                                dataColumn.MaxLength = schemaRow.Size>0?schemaRow.Size:-1;
                            }

                            if (schemaRow.IsReadOnly) {
                                dataColumn.ReadOnly = true;
                            }
                            if (!schemaRow.AllowDBNull && (!schemaRow.IsReadOnly || schemaRow.IsKey)) { // MDAC 71060, 72252
                                dataColumn.AllowDBNull = false;
                            }

                            if (schemaRow.IsUnique && !schemaRow.IsKey && !fieldType.IsArray) {
                                // note, arrays are not comparable so only mark non-arrays as unique, ie timestamp columns
                                // are unique, but not comparable
                                dataColumn.Unique = true;

                                if (!schemaRow.AllowDBNull) { // MDAC 71060
                                    dataColumn.AllowDBNull = false;
                                }
                            }
                        }
                        else if (null == dataColumn.Table) {
                            dataColumn.AutoIncrement = schemaRow.IsAutoIncrement;
                            dataColumn.AllowDBNull = schemaRow.AllowDBNull;
                            dataColumn.ReadOnly = schemaRow.IsReadOnly;
                            dataColumn.Unique = schemaRow.IsUnique;

                            if (fieldType == typeof(string) || (fieldType == typeof(SqlTypes.SqlString))) {
                                //@devnote:  schemaRow.Size is count of characters for string columns, count of bytes otherwise
                                dataColumn.MaxLength = schemaRow.Size;
                            }
                        }
                    }
                    if (null == dataColumn.Table) {
                        if (4 > (int)_loadOption) {
                            AddAdditionalProperties(dataColumn, schemaRow.DataRow);
                        }
                        AddItemToAllowRollback(ref addedItems, dataColumn);
                        columnCollection.Add(dataColumn);
                    }

                    // The server sends us one key per table according to these rules.
                    //
                    // 1. If the table has a primary key, the server sends us this key.
                    // 2. If the table has a primary key and a unique key, it sends us the primary key
                    // 3. if the table has no primary key but has a unique key, it sends us the unique key
                    //
                    // In case 3, we will promote a unique key to a primary key IFF all the columns that compose
                    // that key are not nullable since no columns in a primary key can be null.  If one or more
                    // of the keys is nullable, then we will add a unique constraint.
                    //
                    if (addPrimaryKeys && schemaRow.IsKey) { // MDAC 67033
                        if (keys == null) {
                            keys = new DataColumn[schemaRows.Length];
                        }
                        keys[keyCount++] = dataColumn;
#if DEBUG
                        if (AdapterSwitches.DataSchema.TraceVerbose) {
                            Debug.WriteLine("SetupSchema: building list of " + ((isPrimary) ? "PrimaryKey" : "UniqueConstraint"));
                        }
#endif
                        // see case 3 above, we do want dataColumn.AllowDBNull not schemaRow.AllowDBNull
                        // otherwise adding PrimaryKey will change AllowDBNull to false
                        if (isPrimary && dataColumn.AllowDBNull) { // MDAC 72241
#if DEBUG
                            if (AdapterSwitches.DataSchema.TraceVerbose) {
                                Debug.WriteLine("SetupSchema: changing PrimaryKey into UniqueContraint");
                            }
#endif
                            isPrimary = false;
                        }
                    }

                    if (null != columnIndexMap) {
                        columnIndexMap[unsortedIndex] = dataColumn.Ordinal;
                    }
                    else if (unsortedIndex != dataColumn.Ordinal) {
                        columnIndexMap = CreateIndexMap(schemaRows.Length, unsortedIndex);
                        columnIndexMap[unsortedIndex] = dataColumn.Ordinal;
                    }
                    mappingCount++;
                }

                bool addDataRelation = false;
                DataColumn chapterColumn = null;
                if (null != chapterValue) { // add the extra column in the child table
                    Type fieldType = chapterValue.GetType();
                    chapterColumn = _tableMapping.GetDataColumn(_tableMapping.SourceTable, fieldType, _dataTable, mappingAction, schemaAction);
                    if (null != chapterColumn) {

                        if (null == chapterColumn.Table) {

                            chapterColumn.ReadOnly = true; // MDAC 71878
                            chapterColumn.AllowDBNull = false;

                            AddItemToAllowRollback(ref addedItems, chapterColumn);
                            columnCollection.Add(chapterColumn);
                            addDataRelation = (null != parentChapterColumn);
                        }
                        mappingCount++;
                    }
                }

                if (0 < mappingCount) {
                    if ((null != _dataSet) && null == _dataTable.DataSet) {
                        AddItemToAllowRollback(ref addedItems, _dataTable);
                        _dataSet.Tables.Add(_dataTable);
                    }
                    // setup the key
                    if (addPrimaryKeys && (null != keys)) { // MDAC 67033
                        if (keyCount < keys.Length) {
                            keys = ResizeColumnArray(keys, keyCount);
                        }

                        // MDAC 66188
                        if (isPrimary) {
#if DEBUG
                            if (AdapterSwitches.DataSchema.TraceVerbose) {
                                Debug.WriteLine("SetupSchema: set_PrimaryKey");
                            }
#endif
                            _dataTable.PrimaryKey = keys;
                        }
                        else {
                            UniqueConstraint unique = new UniqueConstraint("", keys);
                            ConstraintCollection constraints = _dataTable.Constraints;
                            int constraintCount = constraints.Count;
                            for (int i = 0; i < constraintCount; ++i) {
                                if (unique.Equals(constraints[i])) {
#if DEBUG
                                    if (AdapterSwitches.DataSchema.TraceVerbose) {
                                        Debug.WriteLine("SetupSchema: duplicate Contraint detected");
                                    }
#endif
                                    unique = null;
                                    break;
                                }
                            }
                            if (null != unique) {
#if DEBUG
                                if (AdapterSwitches.DataSchema.TraceVerbose) {
                                    Debug.WriteLine("SetupSchema: adding new UniqueConstraint");
                                }
#endif
                                constraints.Add(unique);
                            }
                        }
                    }
                    if (!commonFromMultiTable && !ADP.IsEmpty(commonBaseTable) && ADP.IsEmpty(_dataTable.TableName)) {
                        _dataTable.TableName = commonBaseTable;
                    }
                    if (gettingData) {
                        _indexMap = columnIndexMap;
                        _chapterMap = chapterIndexMap;
                        dataValues = SetupMapping(schemaRows.Length, columnCollection, chapterColumn, chapterValue);
                    }
                    else {
                        // debug only, but for retail debug ability
                        _mappedMode = -1;
                    }
                }
                else {
                    _dataTable = null;
                }
                if (addDataRelation) {
                    AddRelation(parentChapterColumn, chapterColumn);
                }
            }
            catch (Exception e) {
                if (ADP.IsCatchableOrSecurityExceptionType(e)) {
                    RollbackAddedItems(addedItems);
                }
                throw;
            }
            return dataValues;
        }

        private void AddAdditionalProperties(DataColumn targetColumn, DataRow schemaRow) {
            DataColumnCollection columns = schemaRow.Table.Columns;
            DataColumn column;

            column = columns[SchemaTableOptionalColumn.DefaultValue];
            if (null != column) {
                targetColumn.DefaultValue = schemaRow[column];
            }

            column = columns[SchemaTableOptionalColumn.AutoIncrementSeed];
            if (null != column) {
                object value = schemaRow[column];
                if (DBNull.Value != value) {
                    targetColumn.AutoIncrementSeed = ((IConvertible)value).ToInt64(CultureInfo.InvariantCulture);
                }
            }

            column = columns[SchemaTableOptionalColumn.AutoIncrementStep];
            if (null != column) {
                object value = schemaRow[column];
                if (DBNull.Value != value) {
                    targetColumn.AutoIncrementStep = ((IConvertible)value).ToInt64(CultureInfo.InvariantCulture);
                }
            }

            column = columns[SchemaTableOptionalColumn.ColumnMapping];
            if (null != column) {
                object value = schemaRow[column];
                if (DBNull.Value != value) {
                    targetColumn.ColumnMapping = (MappingType)((IConvertible)value).ToInt32(CultureInfo.InvariantCulture);
                }
            }

            column = columns[SchemaTableOptionalColumn.BaseColumnNamespace];
            if (null != column) {
                object value = schemaRow[column];
                if (DBNull.Value != value) {
                    targetColumn.Namespace = ((IConvertible)value).ToString(CultureInfo.InvariantCulture);
                }
            }

            column = columns[SchemaTableOptionalColumn.Expression];
            if (null != column) {
                object value = schemaRow[column];
                if (DBNull.Value != value) {
                    targetColumn.Expression = ((IConvertible)value).ToString(CultureInfo.InvariantCulture);
                }
            }
        }

        private void AddRelation(DataColumn parentChapterColumn, DataColumn chapterColumn) { // MDAC 71613
            if (null != _dataSet) {
                string name = /*parentChapterColumn.ColumnName + "_" +*/ chapterColumn.ColumnName; // MDAC 72815

                DataRelation relation = new DataRelation(name, new DataColumn[] { parentChapterColumn }, new DataColumn[] { chapterColumn }, false); // MDAC 71878

                int index = 1;
                string tmp = name;
                DataRelationCollection relations = _dataSet.Relations;
                while (-1 != relations.IndexOf(tmp)) {
                    tmp = name + index;
                    index++;
                }
                relation.RelationName = tmp;
                relations.Add(relation);
            }
        }

        private object[] SetupMapping(int count, DataColumnCollection columnCollection, DataColumn chapterColumn, object chapterValue) {
            object[] dataValues = new object[count];

            if (null == _indexMap) {
                int mappingCount = columnCollection.Count;
                bool hasChapters = (null != _chapterMap);
                if ((count != mappingCount) || hasChapters) {
                    _mappedDataValues = new object[mappingCount];
                    if (hasChapters) {

                        _mappedMode = MapChapters;
                        _mappedLength = count;
                    }
                    else {
                        _mappedMode = MapDifferentSize;
                        _mappedLength = Math.Min(count, mappingCount);
                    }
                }
                else {
                    _mappedMode = MapExactMatch; /* _mappedLength doesn't matter */
                }
            }
            else {
                _mappedDataValues = new object[columnCollection.Count];
                _mappedMode = ((null == _chapterMap) ? MapReorderedValues : MapChaptersReordered);
                _mappedLength = count;
            }
            if (null != chapterColumn) { // value from parent tracked into child table
                _mappedDataValues[chapterColumn.Ordinal] = chapterValue;
            }
            return dataValues;
        }
    }
}
